harmonic

The Harmonic MCP Server provides access to Harmonic.ai APIs for searching companies and professionals, and for retrieving detailed information about companies and people. It ships as a standalone Node.js bundle that runs the Harmonic integration and exposes a set of tools you can invoke from Claude Desktop (or any MCP client) to perform searches or fetch structured data. After starting the server, you configure Claude Desktop (or your MCP consumer) to point at the built index.js so Claude can query Harmonic’s API via the MCP interface.

To use it, first set your Harmonic API key using the harmonic_set_api_key tool. Then you can run the available tools to search for companies, search for people, fetch saved search results, or retrieve employees for a company. The available tools include harmonic_search_company_by_domain, harmonic_search_companies, harmonic_search_people, harmonic_get_saved_search_results, and harmonic_get_company_employees, each with their respective parameters as documented in the README. Ensure you provide the required domain, query, or IDs, and optionally pagination controls like size and cursor to refine results.

Prerequisites:

• Node.js installed on your system (node and npm available in PATH)
• Access to the Harmonic API and a valid API key

Step-by-step installation:

1. Install dependencies and build the standalone package:

npm install
npm run build

2. The build process outputs a standalone package at dist/standalone/ containing all dependencies. Verify the path to the built index:

dist/standalone/index.js

3. Configure your MCP client (e.g., Claude Desktop) to run the server using Node and the built index:

# Example for Claude Desktop configuration
"command": "node",
"args": ["/absolute/path/to/HarmonicMCPServer/dist/standalone/index.js"]

4. Set your Harmonic API key using the harmonic_set_api_key tool (as described in the Tools section) and restart Claude Desktop or your MCP client.

Tips and caveats:

• Ensure the path to the built index.js is absolute and does not contain spaces or special characters.
• Use the full path to Node (find it with which node) when configuring the MCP client.
• Keep your Harmonic API key secure and do not expose it in logs or client configurations.
• The server exposes several endpoints for searching and retrieving data; use the required parameters (domain, query, company_id, etc.) as documented in the README.
• If you encounter authentication errors, verify that HARMONIC_API_KEY is set in the environment where the MCP server runs and that the key has appropriate permissions.
• When upgrading Harmonic API versions, rebuild the standalone package to ensure compatibility with the latest API features.